Ch. 3 Pearson

Questions from the textbook!

What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?

They have both hydrophilic and hydrophobic regions.

Integral proteins are mostly involved in

transport function.

How does water enter and exit a cell?

By simple diffusion or by use of an integral transport protein

A glycoprotein

is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.

Which of the following molecules would be blocked by a cell membrane?

Ions

Hydrophobic molecules move across a membrane

by passive transport directly across the membrane.

What is a hallmark of passive transport across cell membranes?

It occurs along an electrochemical gradient, and may involve the use of transport proteins.

A positively charged sodium ion

would require the use of integral protein channels to pass through a cell membrane.

Which of the following statements regarding active transport is false?

It powers the diffusion of water across the cell membrane.

A laboratory scientist discovers teichoic acid in the blood serum of a patient. This indicates the patient likely has an infection with

Gram-positive bacteria.

Which microorganisms have a thick layer of peptidoglycan?

Gram-positive bacteria

A medical student is examining some Gram stained specimens. She notes that some prokaryotic cells appear purple under the microscope. She concludes they are

Gram-positive bacteria.

Which of these chemicals is in peptidoglycan?

N-acetylglucosamine

Tumbles occur when

the flagella rotate clockwise.

Which of the following types of bacterial cells would have only a single flagellum?

Monotrichous

Peritrichous bacteria make a run when

the flagella turn counterclockwise and become bundled.

Which of the following types of bacterial cells would have flagella located at only one end of the cell?

Lophotrichous and monotrichous

How is simple diffusion different from other types of passive transport?

Simple diffusion does not require a permease.

How is osmosis different from simple diffusion?

Water movement is driven by the concentration of solutes rather than its own concentration.

Nonspecific permeases

allow a variety of molecules to cross the cytoplasmic membrane.

What will happen to a cell that is placed in a solution containing a high concentration of sugar, a molecule that cannot pass across the cell membrane?

The cell will lose its interior water, causing it to shrivel up and possibly die.

One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by

ribosomes

Which of the following is part of the endomembrane system?

golgi apparatus

Which of the following organelles breaks down worn-out organelles?

lysosomes

Where are lipids made in the cell?

smooth endoplasmic reticulum (ER)

What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell?

plasma membrane